While Johnny Cueto could be back in the rotation as early as Sunday, it's hard to believe his recent elbow issues won't affect his trade value as well as his contract demands in the offseason. Do interested teams have a lot to worry about?

They might.

Cueto missed his start on Sunday because of elbow soreness. The Cincinnati Reds sent the right-hander for an MRI and the results found no structural damage on Tuesday, but that may not tell the whole story. Fellow Reds' starter Homer Bailey was said to have suffered a sprained ligament in his throwing elbow in April.

Although surgery was already being considered an option, it was later found he had a significant tear of his UCL and officially needed season-ending Tommy John surgery.

What's alarming is that Cueto's four starts in May have been fairly uncharacteristic. In April he was 2-2 with a 1.95 ERA and 0.729 WHIP in five starts. He's 1-2 with a 4.45 ERA and 1.271 WHIP in four starts this month. On the year he's 3-4 with a 3.03 ERA and 0.964 WHIP in nine starts.

Bailey kicked off 2015 going 0-1 with a 5.56 ERA and 1.765 WHIP in his first two starts before hitting the disabled list.

So far in 2015 there have been a total of 43 pitchers undergo the reconstructive procedure and some of the bigger names dealt with elbow soreness/inflammation, but their initial injuries and/or MRI results did not immediately indicate they suffered a tear in their UCLs or needed surgery at all.

This happened to Zack Wheeler of the New York Mets, Yu Darvish of the Texas Rangers, Brandon McCarthy of the Los Angeles Dodgers, Joe Nathan of the Detroit Tigers and Alex Cobb of the Tampa Bay Rays. Here's a short timeline and breakdown of what happened with these pitchers.

Wheeler - during spring training it was reported Wheeler was dealing with a tender elbow. The right-hander later acknowledged he pitched through elbow pain during his rookie campaign in 2014 and used anti-inflammatory creams and other treatments to keep it at bay. General manager Sandy Alderson later said Wheeler dealt with elbow tendinitis "intermittently" in 2014. An MRI in spring training - which the team said they believed he didn't need - revealed a tear in his UCL.

Darvish - the right-hander left his first spring training start with tightness in his right triceps. He went for an MRI, which revealed a sprained UCL (also considered a partial tear). However, this did not come out of nowhere. Darvish was shut down at the end of 2014 as he dealt with elbow inflammation. What's bizarre is that he had an MRI in November that came back completely clean. The All-Star went 2-3 with a 4.73 ERA and 1.475 WHIP in his final seven starts of 2014 after going 8-4 with a 2.42 ERA and 1.179 WHIP in his first 15.

McCarthy - after a tremendous second half with the New York Yankees in 2014, the Los Angeles Dodgers signed the right-hander to a four-year, $48 million deal. He kicked off 2015 with a 3-0 record, but he racked up a 5.87 ERA and 1.217 WHIP in four starts (23 innings) before exiting a game early because of elbow tightness. McCarthy said he'd been dealing with it since his third start and initial tests for possible ligament damage came back negative. It was believed McCarthy could be dealing with tendinitis, but an MRI soon revealed a torn UCL.

Nathan - the Tigers' closer suffered a Grade 1 flexor strain in his elbow at the onset of 2015. He was shut down for a little while but resumed throwing and was close to returning to the Tigers in late April. However, in his first rehab appearance with Triple-A Toledo the right-hander suffered another apparent elbow injury and immediately left the game. He was diagnosed with a torn UCL and underwent Tommy John surgery a week later (the second such procedure of his career).

Cobb - the Rays' ace was diagnosed with forearm tendinitis in spring training and started the 2015 season on the disabled list. He did not have a lapse in performance, but he was kept out of action until early May, which was when it was discovered he had a full UCL tear. He opted to undergo Tommy John surgery in mid-May.

So while Mark Sheldon of MLB.com reports Cueto will throw a bullpen session on Friday and start on Sunday if the tightness subsides and he's comfortable throwing, it's unknown how much longer the ace will last this season. This could still be a red flag for clubs looking to acquire Cueto at the trade deadline, especially since Darvish had an MRI come back totally clean just a couple of months before he went down for the season.

"A serious arm injury for Cueto would hurt his standing as one of the top free agents on the upcoming open market, whereas an injury would hurt the Reds' chance of righting the ship and potentially eliminate their best trade chip should they sell off veteran pieces this summer," writes Steve Adams of MLBTradeRumors.com.

While the news is considered good right now, elbow inflammation has rarely been something to not be worried about in the past. Teams will likely be keeping a much closer on eye on Cueto over the next couple of months.